/*
 * Copyright 2022-2024 Ponfee (http://www.ponfee.cn/)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.ponfee.disjob.common.concurrent;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * Period executor
 *
 * @author Ponfee
 */
public class PeriodExecutor {

    private final Lock lock = new ReentrantLock();
    private final long periodMs;
    private final Runnable task;

    private volatile long nextExecuteTimeMillis;

    public PeriodExecutor(long periodMs, Runnable task) {
        this.periodMs = periodMs;
        this.task = task;
        renewTime();
    }

    public void execute() {
        if (nextExecuteTimeMillis < System.currentTimeMillis() && lock.tryLock()) {
            try {
                renewTime();
                task.run();
            } finally {
                lock.unlock();
            }
        }
    }

    private void renewTime() {
        this.nextExecuteTimeMillis = System.currentTimeMillis() + periodMs;
    }

}
